Microsoft's deputy general counsel of intellectual property and licensing Horacio Gutierrez said in a statement that the Salesforce.com's CRM product infringed on the company's patents.

The patents cover construction of a websites without coding, mapping between logical and physical data, remote software calls, the placement of objects on a screen, and control of the display. You can read Microsoft's filing here (pdf).

"We have a responsibility to our customers, partners, and shareholders to safeguard that investment, and therefore cannot stand idly by when others infringe our IP rights,' Gutierrez said.

Salesforce.com declined to comment.

Microsoft has a history of aggressively pursuing companies that it believes have infringed on it patents. Usually, the company seeks legal remedy or ongoing royalties for patents use.

Recently, Microsoft has focused its attention on those using Linux. Last year, it brought a suit against sat-nav specialist TomTom, and this year, it signed smartphone maker HTC to a patent protection deal. HTC makes phones for Google using its Android Linux.

Microsoft is also familiar with being on the sharp end of patent litigation. The company is currently getting its pants dusted by i2i Technologies over alleged patent infringement by Word. ®